Signal system.



No. 795,600. PATENTED JULY 25, 1905. w. s. FRANKLIN &-w. R. WHITBHORNE.

SIGNAL SYSTEM:

APPLIOATIOK nun APR 10.1905.

WITNESSES.

Am lnlumlux mmnmvm UNITED STATES PATENT OFFICE.-

SIGNAL SYSTEM.

Specification of Letters Patent.

Patented July 25, 1905.

Application filed April 18, 1905. Serial-No. 256,187.

To all whom it may concern.-

Be it known that we, WILLIAM S. FRANK- LIN, a citizen of the UnitedStates, and WIL- LIAM R WHrrnHoRNE, a subject of the King of GreatBritain, both residing in Bethlehem, Pennsylvania, have invented certainImprovements in Signal Systems, of which the following is aspecification.

Our invention consists in a combination of apparatus comprising a systemdesigned to indicate in the operators cab of a train the condition orposition of successive signals along the line of the track.

One object of the invention is to provide a system,incl u ding apparatuspartly on the train and partly at the ends of each section of track, soarranged in combination with any of the automatic or other signals atpresent in use on railroads that a device in the operators cab of eachtrain will be actuated whenever the train passes from one block toanother or passes over definite portions of the track, and therebycaused to indicate whether said signal is in the danger or in theclearposition or is inoperative.

Another object of our invention is to provide a system having theabove-noted characteristics which shall, while being relatively simpleas regards its parts and their arrangement, require but little attentionto maintain it in operative condition, while at the same time beingpractically certain and positive as regards its operation.

It is further desired to provide a signal system, as above noted, ofsuch a nature that it may be applied to roads already equipped with anyof the ordinary block-signal systems without requiring material changeof or interfering with such systems.

These objects we attain as hereinafter set forth, reference being had tothe accompanying drawings, in which Figure l is adiagrammatic Viewillustrating one set or equipment of the apparatus and connectionsemployed in our system. Fig. 2 is an enlarged View, to some extentdiagrammatic, illustrating a possible form of indicating device for usein the operators cab of a locomotive or train. Fig. 3 illustratessomewhat in detail a possible construction of switch used with awell-known form of semaphoresignal. Fig. 4 is a diagrammatic viewshowing a portion of a track arranged to cause operation of theindicating device on a train from a signal placed at some point otherthan at the end of a block-section, and Fig. 5 is a diagrammatic Viewillustrating a slightlymodified combination of apparatus for carryingout our invention.

In'the above drawings, 6 and t are respectively the rails at the ends oftwo adjacent block-sections of a railroad, these being insulated fromone another, as indicated at i and as required in all of the blocksystems at present in use. It will be understood that as usual there isat each end of each block one or more visual signals-such, for example,as is illustrated in Fig. 3-which when there are no trains in the blockextends in a line forming an acute angle with the vertical and which.

train in the block ahead. In such case the switch controlled by thissignal and described hereinafter would be modified accordingly.

Our system is designed to indicate to the engineer of a train theposition of the signalarm f and as part of the apparatus for carryingout this object we provide a switch f, so supported that it will beclosed whenever the arm f is in its inclined or safe position and openwhen said arm is in its horizontal or danger position. One terminal ofthis switch we connect to the rail-section t and the other terminal toone terminal of a condenser g, whose second terminal is connected to therailsection t. While we have shown in the drawings but a singleequipment of this portion of our system, it will be understood that eachsemaphore along the line has a similar outfit. Upon each locomotive oroperators car we provide a small alternating-current generator a, drivenin any desired manner, and connect one terminal of this to one of thewheels, as Z), of the locomotive electrically insulated from the otherwheels, or said terminals may be connected to the frame of a tender oranother car connected to the locomotive by insulatingcouplings. Thesecond terminal of the generator we ground on the frame of the 1000-motive through two magnet-windings r and s and a switch 2, all connectedin series. This switch is provided with three points, on the first ofwhich, 1, it opens the generator connection to the frame of thelocomotive. When on another point, 3, it places an auxiliary condenser 0in circuit with said generator and the two magnets 'r and s, and on theintermediate point said magnets and the generator are connected inseries between the insulated wheel d and the frame of the locomotive or,what is the same thing, one of its other wheels, 6. If desired, we mayplace in series with the generator an adjustable inductance a for apurpose hereinafter noted.

As shown in Fig. 2, the magnet a is provided with an armature having atrigger 5, whereby an indicating-banner C is maintained in a verticalposition against the action of a spring 9. There is connected to thesaid armature a relatively strong spring 7, opposing movement of saidarmature under the action of the magnet 9' to such an extent that suchmotion cannot occur unless a relatively large but predetermined currentflows through said magnet. The trigger on the armature is so placed thatthe banner is maintained in its vertical position as long as thearmature is not moved toward the magnet.

The magnet s is provided with an armature having a trigger 6 so placedthat as long as said magnet is energized and holds the armature in itsattracted position against the action of a spring 8 a banner D ismaintained in a vertical position against the action of its spring 10.As soon, however, as the magnet s is deenergized said spring 8 causesthe trigger to release the banner, so that'it moves to its horizontalposition, as shown in Fig. 2.

Under operating conditions if a locomotive equipped with the apparatusabove described be moving upon a track within a single blocksection withits generator in operation and its switch 2 in the intermediate positionit will be seen that the alternating current generated will flow throughthe two magnets 7' and 8, through switch 2 and wheel (Z to the track,thence through wheel Z) and the adjustable inductance a back to thegenerator. Under these conditions the current flowing is equal to itbeing noted that this current is determined by the constants of thegenerator and the amount of resistance and inductance in circuit. Thisflow of current energizes the magnet 8 sufficiently to retain itsarmature in position to hold the banner D vertical, though such flowdoes not energize the magnet '1' sufficiently to overcome the effect ofthe spring 7 on its armature, and, as a consequence, the banner C alsoremains in its vertical posit-ion. As the locomotive passes from oneblock to the next there is an interval of time during which the wheelsZ) and (Z occupy the relative positions shown in Fig. lthat is to say,the wheel (Z is upon the rail 25 of one block while the wheel I) engagesthe rail t of the next adjacent block. It now the semaphore-arm f be inthe horizontal position shown in Fig. 3, the switch f is open, and, as aconsequence, the circuit of the generator (0 will be broken. The magnets is therefore deenergized, and the spring 8 moves its armature, so asto release the banner D, which is immediately pulled to its horizontalposition, thus indicating that the signal-arm stands at danger. Eventhough the magnet 1* is also deenergized its banner C is not affected,since there is no movement of its armature. On the other hand, if thesemaphore-arm f be in its inclined position the switch f is closed, sothat when the locomotive occupies the position shown in Fig. 1 arelatively large current is permitted to flow. This excessive fiow takesplace for the reason that the capacity of the condenser g neutralizesthe inductance of the windings s, 9, and a, the amount of the currentbeing given by the formula I I so that it will be seen that said currentis limited only by the ohmic resistance in circuit, where normally it isalso cut down by the inductance of the windings above noted. This largecurrent, preferably about ten times that flowing on short circuit, soenergizes the magnet 4' as to completely overpower the action of thespring 7 upon its armature and causes this latter to release the banner0, which consequently moves to its horizontal position, therebyindicating that the block ahead is clear? Since the armature of themagnet s is already in a position corresponding to the energizedcondition of the magnet, its banner D will remain in the verticalposition. Should the locomotive pass from one block to another withouteither of its indicating-banners C orD being released, it would showthat the main signal system was out of order, as from a short circuitbetween the rails of adjacent blocks, and would indicate the necessityof the engineer proceeding cautiously.

The inductance a is made adjustable, so that the total inductance in thegenerator-circuit may be made of the right amount to be substantiallyneutralized by the capacity action of .the condenser g, as will beunderstood by those skilled in the art.

In order that the engineer may be able at any time to test theoperativeness of the indicating apparatus comprised by the magnets 7'and s and their attached parts, we provide the auxiliary condenser c andthe switch 2. By moving the blade of this switch to the point 3 the safecondition of the main signal system is reproduced and the banner 0should be released, while, on the other hand, the danger condition maybe reproduced by moving the switch-blade to the point 1, therebyopencircuiting the generator and causing release of the banner D if thesystem is properly op erative.

if it be desired to have the indicating apparatus show the position of asignal at some point of a block otherthan at its ends, we may provide asection of track, as insulated from the remainder, as shown in Fig. 4,the two adjacent portions of the main rail, however, being bondedtogether by means of the conductor 6 In this case the switch f is, asbefore, operated by the automatic or manual signal and has one terminalconnected to the rail t and its second terminal connected, through thecondenser g, to the section 25 This arrangement may in many instances beused in place of that shown in Fig. 1, since it would be applicable toany of the existing signal systems without requiring any modificationthereof, where, on the other hand, it is possible that thefirst-described arrangement might necessitate some slight change inexisting systems before it could be applied to them.

While we preferably connect the two wires 12 and 13 of the circuit uponthe locomotive to two wheels insulated from each other and bearing upona common rail, it will be understood that it is not absolutely necessaryto follow this design, since, if desired, one of said wires may beconnected to a brush or auxiliary contact insulated from the frame ofthe locomotive and bearing upon the rail or it may be connected to themetallic frame of a tender or car connected to said locomotive or itsequivalent by insulating-coupling mechanism.

It is to be noted that a great advantage of our system, as abovedescribed, is due to the use of the condensers g, since these in no wayinterfere with present electrically-operated systems using the rails tand t as conductors by reason of the fact that they do not permit of theflow of direct current through them. It will further be noted that it isa practical impossibility for the safe indication to be accidentallygiven on the locomotive except under the predetermined safe conditions,since it is only when the condenser is placed in circuit with theindicating devices that it is possible for the greatly-increased currentto flow. If desired, we may include in the circuit carried by the car orlocomotive a condenser 'g, as shown in Fig. 5, for the purpose ofpreventing the possibility of the indicating devices being actuated bystray direct currents accidentally entering said circuit from the track.

We claim as our invention 1. A signal system including an indicatingdevice on a car, a generator normally supplying an inoperative currentto said device, a main signal, and electrical means responsive only toan alternating current and controlled by said main signal for varyingthe currentfiow through the indicating device under predeterminedconditions of said signal, substantially as described.

2. A signal system including an indicating device on a car, a generatornormally supplying current to said device to an extent insufficient tooperate the same, a main signal, and electrical means includingalternating-current apparatus controlled by said signal for augmentingthe current-flow through the indicating device under predeterminedconditions of said signal, substantially as described.

3. A signal system including an indicating device on a car, a generatornormally supplying an inoperative current to said device, a main signal,and a circuit including a condenser controlled by said signal forcausing a variation of the current-flow through the indicating deviceunder predetermined conditions of the signal, substantially asdescribed.

4. A signal system including a track having a series of insulatedsections, a main signal along the track, a switch controlled by saidsignal, a condenser connected to the switch and with it connected to twoof the track-sections, with a car having an indicating device, and meansfor connecting said device to the rail-sections, substantially asdescribed.

5. A signal system including a track having a series of insulatedsections, a main signal along the track, a switch controlled by saidsignal, a condenser connected to the switch and with it connected to twoof the track-sections, with a car having a circuit including agenerator, and an indicating device, the terminals of said circuit beingboth electrically connected to the track but insulated from each other,substantially as described.

6. A signal system including indicating means on a car havinga magnet,an armature therefor, and mechanism controlled by the ar mature, agenerator operating at a voltage normally insuflicient to operate saidarmature, a main signal, a circuit controlled thereby including meansopen-circuited to direct currents for augmenting the current throughsaid magnet sufliciently to cause it to operate its armature, and meansfor connecting said circuit to said indicating means when the car is ata predetermined point, substantially as described.

7. A signal system including a car provided with indicating deviceshaving two magnets, a generator normally supplying current to saidmagnets insuflicient to operate the armature of one while holding thearmature of the other in its attracted position, with a track for thecar and means along said track constructed to be unaflected by directcurrent for causing the current-flow through said magnets to beaugmented sufficiently to operate the armature of said first magnet,substantially as described.

8. A signal system including a car provided with indicating deviceshaving two magnets, a generator normally supplying current to saidmagnets insufficient to operate the armature of one while holding thearmature of the other in its attracted position, with a track.

&

consisting of a series of sections insulated from each other, a mainsignal for each section, a circuit controlled by each signal andconnecting the adjacent ends of each pair of sections, with electricalmeans including alternating-current apparatus in each of said circuitsfor causing increase of the currentflow through said magnets suflieientto operate the armature of said first magnet as the car passes a givenpoint, substantially as described.

9. A signal system including a track having a number of sectionsinsulated from each other, a series of independent circuits connectingthe adjacent ends of each pair of sections, a switch and a condenser ineach circuit, devices for controlling said switches, with a car or carsoperative on the track having a circuit including an alternating-currentgenerator and an indicating device, the ends of said car-circuit beingelectrically connected to the track independently of each other,substantially as described.

10. A signal system including a track having a number of sectionsinsulated from each other, a series of independent circuits connectingthe adjacent ends of each pair of sections, a switch and a condenser ineach circuit, devices for controlling said switches, with a car or carsoperative'on the track having a circuit including an alternating-currentgenerator and a magnet provided with indicating mechanism normallyunoperated by the current supplied by the generator, the

ends of said car-circuit being electrically connected to the trackindependently of each other, substantially as described.

11. A signal system including an indicating device on a car, analternating-current generator in circuit therewith, a main signal orsignals along the track for said car, a circuit including a condensercontrolled by said signal for causing a variation of the currentflowthrough the indicating device under predetermined conditions of saidsignal, and an adjustable ind uctance also in circuit with saidgenerator, substantially as described.

12. A signal system including an indicating device on a car, a generatornormally supplying an inoperative current to said device, a main signal,and electrical means controlled thereby responsive only to alternatingcurrent for varying the current-flowthrough the indicating device underpredetermined conditions of said signal, with a duplicate equipment ofsaid electrical means carried by the car for testing the operativenessof the generator and indicating device, substantially as described.

In testimony whereof We have signed our names to this specification inthe presence of two subscribing witnesses.

WVILLIAM S. FRANKLIN. lVILLIAM R. WHITEHORNE.

Witnesses:

WILLIAM H. FoL'rz, A. L. Corn.

